Sarcocystis neurona-Induced Myeloencephalitis Relapse Following Anticoccidial Treatment.

The research study is about the relapse of Sarcocystis neurona-induced Myeloencephalitis (a neurological disorder) in mice, after treating them with the anticoccidial drug diclazuril.

Study Objectives

The purpose of this study was:

• To understand how Sarcocystis neurona, a protozoan parasite, behaves in its aberrant host (mouse) after being treated with diclazuril.
• To investigate the possibility of reinfection or relapse in the host after cessation of the treatment.

Methodology

The researchers:

• Infected mice with the Sarcocystis neurona merozoites. Then, 7 days post-infection, some of the mice were treated with diclazuril for either 30 or 60 days while some were not treated at all as control.
• Observed the effects of the diclazuril treatment on the mice and whether they displayed any neurological symptoms of infection.
• Analysis for infection was done through histological examination and also by culture of the cerebellar samples.

Findings

The main findings from the research were:

• The mice that were treated with diclazuril did not show any signs of the disease while being treated. However, within 60 days of the cessation of treatment, they started showing neurological symptoms consistent with Sarcocystis neurona infection.
• The cerebellum samples from all mice showed signs of infection, irrespective of whether they were treated or not. However, only samples from mice showing neurological signs produced viable Sarcocystis neurona in culture. The samples from infected but neurologically normal mice after 30-day treatment didn’t produce any viable parasite.
• The IgM antibody production, part of the humoral immune response, decreased during the treatment and increased after the cessation of treatment, indicating recrudescence of infection.

Conclusion

The overall conclusion from the study was that although the anticoccidial drug diclazuril was effective in inhibiting the replication and migration of the Sarcocystis neurona in mice during treatment, it did not fully eliminate the parasite. This suggested that a relapse or recurrence of the infection after the treatment is stopped is possible. The researchers propose further studies to explore this matter in depth.